Forensic Pathology of Traumatic Brain Injury

Abstract

Traumatic brain injury constitutes a significant proportion of cases requiring forensic examination, and it encompasses (1) blunt, nonmissile head injury, especially involving motor vehicle accidents, and (2) penetrating, missile injury produced by a range of highand lower-velocity projectiles. This review examines the complex pathophysiology and biomechanics of both types of neurotrauma and assesses the macroscopic and histologic features of component lesions, which may be used to determine the cause and manner of death resulting from an intentional assault or accident. Estimation of the survival time postinjury by pathologic examination is also important where malicious head injury is suspected, in an attempt to ascertain a time at which the traumatic event might have been committed, thereby evaluating the authenticity of statements made by the alleged perpetrator.Keywords traumatic brain injury, veterinary forensic neuropathology, artifacts, contusions, axonal injury, cerebral ischemia, brain edema, intracranial hemorrhage, ischemic-hypoxic encephalopathy, gunshot wounds, captive bolt stunning, age of lesions In human medicine, forensic pathology has evolved into a distinct subspecialty. While veterinary pathologists have traditionally been infrequently called on to adjudicate in forensic cases where intentional head trauma is suspected, such cases are becoming more common and require more in-depth forensic knowledge. When an animal presents with signs of external head trauma, such as scalp bruises and skin abrasions, abetted by a reliable history of a traumatic event, a diagnosis of traumatic brain injury (TBI) may be relatively straightforward. However, in the absence of visible evidence of trauma and a reliable history, the onset of neurologic signs may provide the only clue that a traumatic event has occurred, especially since grazing livestock and free-roaming companion animals are not closely scrutinized.In forensic pathology, the timing of tissue responses is often the primary medicolegal task, particularly as it may support or refute statements made by a suspected perpetrator of abuse. These pathologic determinations usually depend on an estimate of the time between a traumatic insult and death. This interval between a traumatic event and circulatory arrest is defined as the survival time and, as such, equates to duration of the brain circulation after injury, although the latter can vary among the brain regions. However, while an estimate of the survival time following head trauma is sometimes possible by the application of relevant histologic and immunohistochemical techniques, the ability to date/age an injury solely on this basis should not be overestimated. 66,75,103 It is not always possible to accurately date TBI lesions because (1) determinations are variously based on studies in humans, experimental animal models (usually laboratory rodents), or both and (2) it is not always stated from which species the data were derived and how these timings were calculated. 46 These assessments are...

Blunt Force Trauma in Veterinary Forensic Pathology

“…The neuropathology of trauma is dealt with separately in this issue 30 and is covered only minimally here. The brain is a vital, highly specialized, and extremely delicate organ intimately surrounded by 3 layers of variably vascularized meninges and encased in protective bone (calvarium).…”

“…For detailed information on timing of neuropathology of trauma, the reader is referred to the review in this journal issue on traumatic brain injury. 30 The liver is one of the most commonly injured organs in the abdominal cavity, and it would be useful to know the timing of liver lesions that occur without obvious changes in the skin or the thoracic/abdominal wall. Acute liver ruptures are characterized, not surprisingly, by extravasated red blood cells (Fig.…”

Histologic safety of transcranial focused ultrasound neuromodulation and magnetic resonance acoustic radiation force imaging in rhesus macaques and sheep

“…, necrosis, red blood cell engulfment (erythrophagocytosis), and intracellular red blood cell breakdown (hemosiderin-laden macrophages)) were noted in areas of red blood cell extravasation. However, acute hemorrhage can be histologically indistinguishable from post-mortem red blood cell extravasation (Finnie, 2016). Thus, a delayed euthanasia timepoint was established to confirm that red blood cell extravasation was indeed a post-mortem tissue extraction artifact rather than true pre-mortem hemorrhage.…”

Vitality and wound-age estimation in forensic pathology: review and future prospects

“…Mechanical brain injury is frequently associated with intracranial haemorrhage, including epidural, subdural, subarachnoid, and brain parenchymal bleeding. Haematoxylin-eosin and immunohistochemical staining are used to evaluate the age of a haemorrhage [79][80][81].…”